Bolt anchor



y 1933- c. c. TOMKINSON BOLT ANCHOR Filed Oct. 1, 1950 INVENTOR (War/s: C" Emil/7 0 MA 458 W ATTORNEYS |||u|| n| Illllllillllllllllllll lllllllllllllflfl) Patented May 16, 1933 CHARLES- c. ronxmson, or naturism), NEW JEnsEY, ASSIGNOR 'ro J. EDWARD OGDEN COMPANY, me, or JERSEY v mam ensues, nnwqnns iy, AJCORPOBATION 01 NEW no m ncnon This invention relates to. bolt anchors adapted for forming anchorages in material not adapted to directly receive and hold'a threaded element, such for instance, as brick, stone or cementitious material. V

This invention has for its salient object to provide an anchor. that is simple and practical in construction, comprises a minimum number of parts and will form. an efiicient anchorage. p Another objectof theinvention is to provide an anchor that can be easily and. quickly expanded to anchoring position.:

Another object of the invention is to provide a simple and inexpensive, method of forming an anchor constructed in accordance with the invention.

Further objects of the invention will appear from the following specification taken in connection with the drawing, which forms a part of this application, and in which Fig. 1 is a'sectional elevation showing an anchor constructed in accordance with the invention disposed in a wall opening and prior to expansion;

Fig. 2 is a view similar to Fig. 1 showing the method of expanding the anchor and the anchor expanded;

Fig. 3 is an elevational view showing the spiral of hard metal which is embedded in the anchor;

Fig. 4 is a similar view of the same part, of modified form;

Fig. 5 is a sectional side elevation of the anchor;

Fig. 6 is an end View of the anchor;

Fig. 7 is a view similar to Fig. 5 but showing a slightly modified form of spiral;

Fig. 8 is a sectional elevation of a mold for making the anchor, showingthe method of making it; and

Fig. 9 is an end elevation shown in Fig. 8.

The invention briefly described consists of an anchor comprising a substantially cylindrical shell formed of relatively soft metal,

such as lead having embedded therein a spiral formed of substantially flat stock of relatively hard metal. The anchor is formed by'placing the hard metal spiral in a cylinvolutions of the spiral.

of the parts drical imold and pouring the lead into the mold around an axially disposed cylindrical core, .thus, filling'the spaces between thecon- Further details of the invention will appear from the following description. 7 o

Theanchor, in the embodiment of the invention illustrated in the drawing, consists of a substantially cylindrical shell 10 formed of soft or ductile metal, such as lead, having embedded therein a spiral coil 11 formed of relatively hard metal. The spiral coil, as shown particularly in Fig. 3, is formed of fiat stock and the end convolution 120i the 'coil extends substantially around a complete circle forming a washer for the outer end of the anchor or the end engaged by the expanding tool.

Instead of forming a normal i surface ,12 x

at an end of the hard metal spiral, the latter'maybe cutoff at desired length from a continuousspiral, forming a structure like that shown in Fig. 4, at 11A. Also the spiral coil 11 1 maybe formed of dishedor concaved stock, as :shown inFig. 7.

1 and2 illustrate the manner of.

using the anchor. The anchor is first placed on a bolt or a threaded element havin a head? and; the head of the boltand theanc or are inserted. in thewall opening. 1 A tamping-tool, such as that shown at 15 in Fig. 2, is then placed at the outer end of the bolt and is tamped. against the outer end of the anchor, the endlof the tool engaging,

the Washer 12 formed on the outer end of the spiral coil 11. -The end coils of the spiral prevent'the tool from burying into the leadduring'expansion, which if it occurred would not only lessen the expansive eflf'ect H but would bind the tool and prevent it from being withdrawn.

n As the tool is struck with a hammer or other suitable impact device the ductile metal will slip on the hard metal spiral and willbe forced laterally into firm gripping engagement with the wall opening. The

hard metal coil facilitates the expansion of the anchor and causes a uniform'expansion throughout the length thereof. It has been found inpractice that when a solid mass of lead is tamped in a wall opening it expands principally atthe ends and if the mass is relatively long there will be very little expansion at the central portion thereof. However, by using the hard metal spiral coil embedded in the soft metal a uniform expansion is obtained throughout the length of the anchor. As the hard metal spiral is shortened during expansion of the anchor by end pressure it also expands'laterally, thereby increasing the gripping engagement and also reinforcing the ductile metal.

Fig. 7 shows a device like that illustrated in Fig. 5 except that the hard metal spiral, instead of being made of flat stock, is curved or dished in cross section as shown at 11B.

Figs. 8 and 9 illustratethe method of making an anchor constructed in accordance with the invention. In these figures there is shown a two part mold comprising sections 20 and 21 and the flat spiral coil 11 is disposed horizontally between the two sections. A core 22 is thrust through the center of the spiral and through the ends of the mold and the soft metal is melted and poured into the top of the moldand fills in the spaces between the convolutions of the spiral coil 11.

From the foregoing description it will be seen that a simple, practical and efficient anchor has been designed and that the anchor can be easily and quickly expanded into engagement with the wall opening. Furthermore, by reason of the construction described a uniform ex ansion will be obtained throughout the ength of the anchor. It will also be clear that a simple, practical and inexpensive method of manufacturing the anchors has been developed, as shown particularly in Figs. 8 and 9.

Although specific embodiments ofthe invention have been particularly shown and described, it will be understood that the invention is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may he made without departing from the spirit or scope of the invention, as expressed in the fol-lowing claims.

VVha-t I claim is:

1. A bolt anchor having a substantially cylindrical body portion of relatively soft deformable material having embedded therein a spiral coil of relatively hard metal, one end of the coil being fiat and substantially covering the outer end of the, anchor.

2. A bolt anchor having a substantially cylindrical body portion of relatively soft expansible material having embedded thereto provide a spiral slip joint between the coils of the soft material.

3. A bolt anchor comprising a coil of relatively hard, fiat metal, the spaces between the convolutions being filled with ductile material, whereby the coil of relatively hard metal separates adjacent portions of the due tile material and prevents said portions from gripping together during expansion there- 4. A bolt anchor having a substantially cylindrical body portion of relatively soft deformable material having embedded therein a spiral coil formed of concaved ribbon of relatively hard metal.

5. A bolt anchor comprising prior to expansion, a tubular shell of relatively soft deformable material, and a spiral coil of relatively hard metal embedded in said shell and extending substantially throughout the thickness of said shell.

6. A bolt anchor comprising a spiral coil formed of relatively hard flat ribbon disposed substantially at ri ht angles to the axis of the coil, and de ormable material filling the spaces between the successive convolutions of the hard metal coil, said deformable material being substantially square in cross section.

CHARLES C. TOMKINSON.

in a spiral coil formed of relatively flat stock of relatively hard metal, the adjacent portions of the soft spiral body portion being initially separated by thehard metal spiral coil, whereby said hardmetal coil is adapted 

